Bioaccessibility and antioxidant activity of curcumin after encapsulated by nano and Pickering emulsion based on chitosan-tripolyphosphate nanoparticles.

In the current study the influence of different lipid-based formulations (Pickering and nanoemulsions) and their droplet size on curcumin encapsulation and bioaccessibility, as well as on its anti-oxidant activity was investigated. Oil-in-water Pickering emulsion stabilized by chitosan-tripolyphosphate (CS-TPP) nanoparticles and nanoemulsions containing an organic phase (Span80:Tween80), were prepared with either medium chain triglyceride (MCT) or corn oil as long chain triglyceride (LCT). An in vitro gastrointestinal (GIT) model consisting of mouth, gastric and intestinal phases was used to characterize the rate and extent of lipid phase digestion of the ingested samples. A centrifugation method determined fraction of curcumin released into mixed micelles after digestion (bioaccessibility). These findings showed that after subjecting to simulated GIT model, all the emulsion systems experienced a progressive increase in mean particle size, due to droplet flocculation and coalescence after digestion. Electrical charge (ζ) of particles was observed to become highly negative as they passed through GIT due to accumulation of anionic bile salts, phospholipids and free fatty acids at their interfaces. The rate and extent of lipid digestion and bioaccessibility of curcumin increased with decreasing mean droplet diameter (NMCT>NCO>PMCT>PCO). Finally, we showed that as compared to free curcumin, the encapsulated curcumin showed higher radical scavenging activity (RSA), which confirmed the protective effect of the emulsion systems on the antioxidant activity of curcumin.

Green-step assembly of low density lipoprotein/sodium carboxymethyl cellulose nanogels for facile loading and pH-dependent release of doxorubicin.

In this study, a simple and green approach was developed to produce a novel nanogel via self-assembly of low density lipoproteins (LDL) and sodium carboxymethyl cellulose (CMC), to efficiently deliver doxorubicin (DOX) to cancer cells. Under optimal conditions, the stable nanogels were of spherical shape with an average diameter of about 90 nm, PDI<0.3 and a zeta potential -35 mV. Furthermore, the cationic anticancer drug, doxorubicin (DOX) was effectively encapsulated into LDL/CMC nanogels with an exceptionally high encapsulation efficiency of ∼ 98%. The release of DOX from DOX-LDL/CMC nanogels was pH-dependent, and DOX was released at a quicker rate at pH 6.2 than at pH 7.4. Importantly, the DOX-LDL/CMC nanogels were shown to effectively kill cancer cells in vitro. The IC50 of the DOX-LDL/CMC nanogels in HeLa and HepG2 cells was approximately 2.45 and 1.72 times higher than that of free DOX. The slightly reduced antitumor efficacy was primarily due to the less cellular uptake of the DOX-LDL/CMC nanogels, which was confirmed by confocal laser scanning microscope (CLSM) and flow cytometry analysis. The high DOX payload and pH-dependent drug release rendered LDL/CMC nanogels as an efficient carrier for doxorubicin and possibly be used for other cationic drugs in different biomedical applications.